Such a shielded lost-concrete container comprises a vessel having unitary walls and floor. A lid blocks the upwardly open mouth of the vessel and is normally also formed of concrete by pouring in concrete once the container is filled with radioactive wastes. Such a shield container cannot also be used as a treatment vessel for the drying of its contents by heating it with its contents under vacuum.
It is also known to transport and store spent fuel elements in cast-iron or -steel containers with a wall thickness of at least 40 cm. Externally these containers have heat-exchange ribs and the cover or lid of such a container is also usually a casting of the sam metal as the vessel it is closing. Such containers can also be used to treat the wastes, typically by heating them while exhausting vapors generated in them by the heat. In this manner the wet but mainly solid phase of matter filtered out of the cooling circuit of a nuclear-power plant can be dried out for permanent storage disposal.